History of Life Flashcards
define macroevolution
broad pattern of change above a species level
what does macroevol tell us about
emergence of terrestrial vertebrates, mass extinctions, origin of flight in birds
when did earth form
4.6 bya
did early earth have lots of O2
no
process how life originated
- abiotic synthesis of small organic molecules
- joining of smaller mlecules into macromolecules such as proteins and NA
- Packaging of macromolecules into protocells(droplets w/ membrane that separated inside protocell from external env)
- Origin of self-replicating molecules that eventually made inheritcance possible
what is the fossil record biased towards
- hard animals
- widespread distribution
- lived for long
what are the 4 major eons
Hadean, Archaean, Protozeric, Phanerozoic
hadean
beginning of planet to 4 bya
archaean
4 bya to 2.5 bya
proterozoic
2.5 bya-.5 bya
phanerozoic
.5 bya-present
what eras is the phanerozoic divided into
paleozoic, mesozoic, cenozoic
what organisms have dominated life for the majority of time
microbes
when did the first single-celled organism form
3.5 bya
what were earth’s sole inhabitants for 1.5 by
Prokaryotes (bacteria + archaea)
what are the oldest known fossils and when
stromatolites(3.6 bya)
when did O2 begin accumulating
2.7 bya from photosyntehsizing organisms
when was the O2 rev
2.7-2.3 bya
inc O2 levels by 3-4 orders
some were poisoned by this- many prok went extinct
when were the first eukaryotes
1.8 bya via endosymbiosis
when were the first multicellular euk
small algae 1.2 bya
larger and more diverse euk(plants, animals, fungi) not in fossil record until….?
600 mya
multiellularity evolved independelty
cambrian explosion
small window of time(10 million)
btwn protozoic and phanerozoic
appearance of fossils resembling modern animals
first evidence of predator prey interactions in fossil record
soft bodies appeared after
colonizing land
500 mya- fungi, animals, plants on land 420 mya- vascular tissue in plants 365 mya- tetrapods evolved from fish 6-7 mya- origian of human lineage from chimps 200,000 ya- origin of modern humans
what has influenced patterns of diversity
plate tectonics, mass extinctions, adaptive radiation